PB1963: A RARE CASE OF MULTIPLE SOLITARY PLASMOCYTOMA
Authors: Z. Mlayah, N. Slama, B. Wiem, B. A. Nouha, B. sarra, L. Adnene
Journal: HemaSphere (2022)

Background: Plasmacytoma is a rare hematological malignancy characterized by extramedullary plasma cell infiltration. It is exceptional in its multiple form. It often affects males with a median age between 55 and 60 years. According to the international myeloma working group, the diagnosis of multiple solitary plasmacytoma is made by objectifying more than one bone or extramedullary plasma cell lesion, absence of monoclonal IgM gammapathy in the blood and urine, absence of spinal cord damage, normal skeletal survey, no end-organ damage. Biologically, monoclonal proteins in serum or urine are detected. Sataging and evaluation are based essentially on the magnetic resonance imaging (MRI). The treatment is based mainly on radiotherapy, chemotherapy and, in some cases, on an autologous hematopoietic stem cell transplant or surgical treatment. Aims: Given the rarity of plasmocytoma and specially the multiple solitary plasmocytoma, very few cases are published in the literature. In this work, we will report a case of multiple solitary plasmacytoma in order to enrich the bibliography as well as to better define the clinical, biological and radiological characteristics of this hemopathy. Methods: we encountered only one case of multiple solitary plasmocytoma in our department that we are going to postpone. We used literature searches to identify previously reported cases of multiple solitary plasmocytoma. Results: The patient is a 61-year-old male with no notable pathological history, smoking at 30 pack-years. As functional signs, there was a weight loss of 10 kg in 6 months and lumbar spine pain. On clinical examination: the performance score was 3, the chest mass was 15 x 8 x 4 cm, absence of anemic syndrome and absence of sensory or motor deficit. The MRI showed a mass of left thoracic soft parts with medullary extent and lumbar and spinal retroperitoneal masses (L3-S1). The biological assessment showed normocytic normochrome anemia at 8.2 g /dL, hyperprotidemia at 108 g / L, absence of hypercalcemia or renal failure. 24-hour proteinuria was 7.21 g, microglobulin β2 was 16.03 mg/L, lactate dehydrogenase levels were normal. The positive diagnosis was made on a biopsy of the chest mass showing tumor cells expressing intensely the CD138 and not expressing the CD3, the CD20 or the CD79a. The osteomedullary biopsy showed the absence of infiltration and the karyotype on marrow by the technique “fluorescence by hybridization in situ” was normal. A monoclonal peak with IgG kappa was objectified in the serum immunofixation. Urinary immunofixation showed the presence of Kappa free light chains and serum free light chain assay showed an increased Kappa/Lambda ratio. The patient was treated with chemotherapy courses based on cyclophosphamide, anthracycline (Doxoribicin) and corticosteroid therapy. Decompressive radiotherapy sessions were indicated for intense spinal pain and sensory-motor deficit installed in both lower limbs. The evolution was marked clinically by the regression of the tumor mass but persistence of spinal pain, biologically by the disappearance of the anemia and the hyperprotidemia. Summary/Conclusion: To conclude, multiple solitary plasmocytoma is rare. It’s clinical, biological and radiological characteristics are particular. Given it’s rarety, there is no specific protocol for staging and treatment. Thus, it is important to collect a sufficient number of patients to develop a protocol allowing a special care for this type of hemopathy.